"so your idea may be interesting but a lot of work in reality and the result will be somewhat similar to 1 or 2 path" (this quoting mechanism here is too much work for me lol)

I don't think it would be that similar! Because if you have say 30 units in a and only 10 in b, c and d, you can move 30 form a to b but only 10 can end up in e because only the units from d can reach e. So yeah, if you've got 10 in each except e it's kinda like a centipede, yeah. But other than that... It just like it for it's "realism".

"[1 unit path + 1 unit anywhere + 1 unit path]"

That's also an interesting idea!